Verify that the power supply unit is fully plugged into the router and a working electrical outlet. Also, verify that the power supply unit is not defective. You can do this by testing the power supply on another router or similar device that uses the same power supply unit. If it is damaged, obtain a new power supply that outputs a minimum of 12V 0.5A.

If the power supply if working, then the power connector on the router is defective. If you are comfortable with soldering, follow this guide to replace the barrel power connector. If you do not want to perform any soldering, follow this guide instead to replace the entire motherboard.

The specified maximum distance for Wireless-G routers is 100 meters or 328 feet. The wireless signal grows weaker as your devices moves further away from it. The signal will also be weaker if it has to travel through walls. Reduce the distance and number of walls between the router and the devices to improve the signal.

If the antenna ports on the router itself are defective, you need to either replace the antenna ports themselves or the entire motherboard unit. If you are comfortable with soldering, follow this guide to replace them. If you do not want to perform any soldering, follow these instructions to replace the entire motherboard.